The use of continuous insulation is mandated for some climates in the United States by newer energy codes. The purpose of continuous insulation is to eliminate thermal breaks that reduce thermal efficiency of insulation placed between framing members such as wall studs.
One efficient and technically sound exterior wall assembly that can function in all climates without any theoretical potential for condensation is a wall assembly in which rigid insulation boards or foam are placed outside of an air barrier (AB)/weather-resistive barrier (WRB) (i.e., within the wall drainage cavity). Such a wall assembly is often referred to as a “work everywhere wall.” The use of continuous insulation in such a wall assembly requires the use of frequently placed conventional ties to connect the wall cladding (i.e., paneling, masonry, or other types of cladding) to the backup wall. The function of these ties is to transfer lateral loads such as wind loads from the cladding to the back-up wall which acts as the structural support for the cladding.
In most masonry assemblies, metal masonry ties need to be installed at 16 inches on center in horizontal and vertical directions to meet building code requirements. These metal ties pass through the continuous insulation and result in thermal breaks that reduce the efficiency of the continuous insulation.
Many commercially available metal ties are made using galvanized steel. When such ties are integrated into the wall assembly, they cannot be replaced without removal of the masonry veneer. The life expectancy of masonry veneer is anticipated to be more than 70 years. During the life cycle of steel masonry ties, they are exposed to the environment within the wall cavity which is constantly moist. This environment and damage to the galvanizing layer caused during installation can cause corrosion of the metal ties. In some cases, structural collapse of the masonry veneer due to corrosion of metal ties has been documented.
When using continuous insulation, the differential temperature between the cladding materials and the back-up wall construction is increased. This temperature differential, along with other factors such as moisture related volume changes, can lead to significant in-plane differential movements between the cladding material and the back-up construction.
The present inventor recognized the need for an improved cladding tie that reduces thermal bridging where the ties penetrate the continuous insulation. The present inventor recognized the need for an improved cladding tie that is less susceptible to deterioration by moisture and weather conditions.
Cladding can move differentially from a back-up wall due to a number of reasons, such as thermal movements, movements caused by moisture expansion of cladding, differential structural movements between the back-up wall and the cladding wall, and seismic movements. The present inventor recognized the need for a cladding attachment device that can accommodate in-plane differential movements between the cladding material and the back-up wall construction.
The present inventor recognized the need for a cladding attachment device that would be easy to install. The present inventor recognized the need for a cladding attachment device that can be efficiently installed in such a manner that the accommodated in-plane differential movements can be in any in-plane direction without a need to set a starting point of movement in the attachment device.
When installing continuous insulation panels, the panels are often installed in complete contact with the AB/WRB on the back-up surface. This prevents proper drainage of water on the exterior face of the AB/WRB. Water can be trapped in the minute gap between the continuous insulation and AB/WRB due to capillary action. This trapped water can cause accelerated deterioration of ties and other components.
The present inventor recognized the need for an improved cladding tie that creates a gap between the continuous insulation panels and AB/WRB. This gap facilitates drainage.
Conventional cladding ties do not provide any mechanism for ensuring that the continuous insulation panels are held in place. As such, continuous insulation panels are often installed with adhesive backing to ensure they stay in place. This adhesive backing can impede drainage of water on the drainage plane and can degrade and fail over time under certain circumstances. This adhesive backing will also results in additional labor and material costs.
The present inventor recognized the need for a cladding tie that can retain the continuous insulation panels in place and eliminate the need of reliance on adhesive backing.
Certain building codes restrict the length of conventional metal ties to 4 inches because longer length conventional ties are susceptible to buckling under compressive load. The present inventor recognized the need to transfer some compressive force from the cladding tie onto the insulation to reduce or eliminate the possibility of buckling under compressive loads and to reduce the effective span of the tie shaft within the cavity.